The present invention relates to mechanical drive trains in which a motor is connected to a load through one or more rotating components, including drive shafts, couplings and gear boxes. More particularly, the present invention pertains to methods and devices used to detect discontinuities in a drive train caused by broken drive shafts, loose couplings, gear failures and the like.
Many machines employ rotating drive trains to transmit power from a motor to a load. Frequently, such drive trains include a connected sequence of different rotating components, including drive shafts, couplings and gear boxes. One example of such a machine is a lifting hoist. The drive train in the hoist will have an electric motor on one end, coupled to a brake drum on the other end. In many such applications, a component failure in the drive train can cause a catastrophic failure of the machine, such as a load drop, and present a threat to the safety of the persons using or working around the hoist. Accordingly, prompt detection of drive train discontinuities that can lead to such a failure is critical.
Attempts have been made in the prior art to monitor mechanical drive trains for discontinuities using a programmable logic controller and a custom ladder-logic style program tailored to meet the needs of the specific drive train. However, these systems require separate hardware and software input from the drive unit itself. A system which integrated the necessary components directly into the drive unit would therefore be more efficient and flexible for accurately detecting and responding to all discontinuities in a complex mechanical drive train.